Employ the New Zealand white rabbit as a model to investigate the toxicity of the combined use of radiation & adriamycin on the heart. Perform two parallel studies. In one, a fractionated course of radiation will be delivered to the heart followed by protracted administration of adriamycin. In the other, protracted adriamycin administration will be followed by a fractionated course of radiation to the heart. Employ the lowest fractionated radiation dose which will not produce cardiac lesions and the highest fractionated dose which is estimated to produce radiation induced heart damage in approximately on-half of the animals. Establish white blood and platelet counts baseline values on every animal. Determine possible additive, antagonistic, or synergistic effects of radiation plus adriamycin under experimental design employed.